Automatic telephone system



March 16 1926.

- CZ. GILLINGS ET AL AUTOMATIC TELEPHONE SYSTEM Filed 001:- 12, 1921 3 Sheets-Sheet 1 Inuau are 2 Charles Eflhflgs-Hmhardlfarn ar March 16,1926. 1,576,740

c. GLLINGS'EI AL AUTOMATI C TELEPHONE SYSTEM Filed Oct. 12, 1-921 3 Sheets-Sheet 2 g film Iharlss Efllmgs-Hmharfiffierca:

March 16 1926.

I 1,576,740 r c. GILLINGS E! Al.

AUTOMATIC iIE LEPHONE SYSTEM Filed 0ct.'12, 1921 3 Sheeis-Sheet 5 Patented Mar. 16, 192%;

CHARLES GILLINGS AND RICHARD MERCER, BX MESNE ASSIGNMENTS, TO AUTOMATIC A CORPORATION OF 1)ELAVVAIBJL.

OF LIVERPOOL, ENGLAND, ASSIGNORS, ELECTRIC INC., OF CHICAGO, ILLINOIS,

. AUTOMATIC TELEPHONE SYSTEM.

Application filed October 12,1921. Serial No. 507,365.

To all 1072 om it may concern Be it known that we, CHARLES GILLINGS and Rrcrmnn MERGER, both subjects of the King of Great Britain and Ireland, and both" residents of Liverpool, England, have invented certain new and useful Improvements in Automatic Telephone Systems, of which the following is a specification.

The present invention relates to improvements in or relating to measured service telephone systems and more particularly relates to an arrangement for enabling connec- 'tions to be charged for at varying rates.

Ilt'has already been proposed to vary the charge according to the junction line taken into use, but obviously this system is only truly applicable where each exchange has direct access to every other exchange in the system and it does not therefore render'possible the charging of varying rates where exchanges are in serial relationship. We have proposed in our British Patent Nunr her 122,747 in such cases, to make a charge equal to the sum of the rates of the trunk lines taken into use.

It has also been proposed in telephone systems employing registering mechanism for controlling the extension of a circuit to :1 called line to vary the period for which one unit of charge is made in accordance with the setting of the registering mechanism for the first digit of a called partys number.

It is the object of the present invention to provide arrangements whereby the charges between any two exchanges in an area may be assessed entirely independently of the route taken, irrespective of'whether the call is set up direct or through one or more in termediate exchanges, and inthe case of automatic telephone systems, irrespective of the. number of digits which determine the exchange in which the connection is finally set up. Consequently, it is possible for the tra'fiic department to fix the charging rate according to the geographical distance between exchanges without reference to the actual lay out of a system.

According to the present invention, this is effected by providing a selecting device which. is adapted to select. the charge to be .matic lay out of a system I changes in which the charging rate is determade for a given connection as determined jointly by the exchange at which the call originates and the" exchange at which the connection is finally established to the wanted party, for instance,a device may be permanently associated with the originating exchange and may be operated in accordance with certain defined characteristics of the destination exchange or similarly the device may be located at the destination exchange and operated in accordance with certain defined characteristics of the originating exchange.

The invention will be better understood by referring to the accompanying drawings in which Figures 1, 2 and 3 illustrate one example of carrying the invention into effect where the call is routed through a number of exchanges in serial relationship. Figure 4 shows a construction applicable where the charging rate may be determined by dialling one more digit additional to that determining the first trunk line over which the call isto be set up; Figure 5 shows a diagrameinbracing 17 exmined in accordance with the distance.

Referring to Figures 1, 2 and 3, it will be assumed that a subscriber at substation A desires to set up a connection with a subscriber in the exchange in which the connector H (Figure 3) is located. For convenience, referring to Figure 5, it will be assumed that the subscriberA has his line connected to exchange Number 1, and that theconnector H is located in exchange Number 17, so that the call must be routed through an intermediate exchange: 13. The connection would be set up in the usual way, the line switch C antomatically operating'on the subscriber at substation A lifting his receiver to find an idle selector whichiit will be assumed is the selector D. The selector D therefore responds to the first digit dialled and subsequently" commences to rotate automatically in search. of an idle trunk the intermediate exchange 131 It will be as sumed that the lines 21 and 22 are the conductors of the first trunk line which is idle. At the outgoing end of this trunk line, is

allocated: a. repeater; E. which. is adapted'go line leading to repeat the subsequent impulses dialled by the subscriber. At the other end oil the trunk lines 21 and 22, is a selector F which is substantially identical in construction with the selector D previously mentioned. This selector responds to the first set of innpulses repeated by repeater E to bring its wipers to the level in which the trunk lines leading; to exchange Number 17 are located. It will be assumed that the lines and 24 are the conductors of the first trunk line which is .t'ound idle. At the outgoing end of this trunk line is a repeater G which functions sii'nilarly to the repeater E. while at the other end or the trunk line is located a seleetor K which responds to the next series of in'ipulses, so that its wipers come opposite the level of a group of connectors in the contact banks of which is located the line ot the party required. It will be assumed that the connector H. is the first idle line which responds to the last two digits to establish connection with the line of the party required.

Before proceeding with the description of the metering, it will be well to point out that when the repeaters E and G are taken into use, the release relays 2-6 and 27 are operated in the usual way, and at their armatures 2S and 29 complete a circuit for the polarizing windings of relays 30 and 31, the other windings of relays SO and 31 being normally connected across the trunk lines, so that the direction of current through the other winding of relay 31 depends upon whether the back bridge relay 32 in the connector H is operated or not, while the current through the other winding of relay 3O depends upon whether the reversing relay 83 ot repeater G is operated. Reversing relay 33 is identical in operation with the reversing relay 3% of repeater E which it will be seen operates when relay 30 is energized. Now the windings of the polarized relay 80 and 31 are so arranged that the relay will not enerp' ze it each windingis excited separately or it the two windings are excited together. but in opposition to each other. llhen however, the two windings assist, the relay' immediately energizes so that the relay 31 responds on the energization of the oath bridge relav 32. Relay 33 then enerand reverses current over the trunk meters 21 and 22 so that relay 30 eners "followed by tie cnergization of relay This 0 ieration as is well known, takes place as soon as the wanted subscriber replies. and does not take place if the wanted subscriber does not reply or it the call should be mace through a connector in which the back bridge relay does not reverse the cur rent, that is to say, a connector which is only accessible to stations to which a call is not to be charged for.

On the completionof the dialling, when it is once ascertained that the subseribefs line is idle, the wiper relay 35 operates and is locked operated in the usual manner. Armature 36 is then attracted completing a circuit for relay 3'? as follows:Earth, worting contact of armature 36, armature 38 and its resting contact, resistance 39, winding of relay 3? to battery. The resistance 39 is such that the relay 3? will only be partially energized, sutlicient to bring its armature 10 into contact with its working contact, armatures ill, 42 and l3 not being operated at this time. Armature i0 is connected to a common lead to which earth is connected momentarily once per revolution of a shaft carrying the cams 4st, 45, l6. On the instant that earth is connected as described, to the :cinmon lead by means of the cam 4 1-, a direct energizing circuit is provided for relay 37 which imlneoiately pulls up the other armatures 41, 4-2 and ll At armature a1 a locking circuit is provided through the back contact of armature l7, while at armature 43, a circuit is closed to a common lead 48 to which booster battery is connected in cycles or impulses by means of the cam operating on the springs 4-9. The booster impulses as will be seen are connected to the lower talking; conductor on the side which has direct connection to the intermediate e3:- change No. 13. The cam 46 being located in exchange No. 17 is adapted to send out 17 ii pulses over the lower talking conductor n nich, by referring to repeater \T, it will be noted are adapted to cause the energization of magnet 50 of a step by step switch S individual to the repeater, he magnet 50 responding' to booster impulses to advance the wipers 51 and 52 of the switch S to the 17th contact, while at the same time at its armature 53, it repeats the booster impulses over the lower talking conductor 2'2 thereby cansing the energization ot the magnet 5 1 of a step by step switch. Q. individual to the repeater E. lonseqnently, the wipers 55 and 5:; of this switch are stepped to the 17th contacts 57 and respectively. The mag:- net 5% also repeats booster impulses over the lower talking conductor at its armature but these are of no etfeet the repeater E is lO-Ctd'Ct at the originating exchange.

It will be understood that the excl'ianges are given arbitrary numbers. independent entirely of the number scheme adopted for dialling purposes, and by arrangfiin the transmission of 17 impulses 0 en" the trunk lines back to the originating}; e7-;- change the switch serves to determine at the originatinp exchange, the exchange where the connection has finally been estalnielied and theretore serves as a means for selecting; the charge to be made in any particular case.

Reterriup; to Figure 5,-the dotted circles drawn with exchan to. 1 as a centre, serve to determine the successive rates of charge,

within the smaller circle the charges will be at unit rate, within the second circle the No. 17 from exchange No. .1 should he charged at 3 t mes un1t rate, and it will be noted that the 17th contact 5? of which Q is connected to a common lead 59 over which three impulses are transmitted during one revolution of the shaft carrying the cams 6065 inclusive. If the exchange No. 17. had been located in either the second or -tourth circles, all that would have been necessary to vary the charge would be to arrange that the contact 57 instead of being connected to lead '59 would have been connected to lead 66 or lead 67 respectively. Consequently, to vary the charge for any exchange or to make any alteration in the charging rates, all that is necessary is vary the connections to the contacts wiped over by wiper 55. After the 17 impulses have been transmitted over the lower talking conductor by the 'cam 46, the cam 45 operates the springs 68 so as to connect earth to the common lead 69, and thereby cause the energization of stop relay 70. This circuit may be traced as follows Earth, contact springs 68, common lead 69, armature 42 and its working contact, winding of relay 70 to battery. Relay 70 energizes and establishes a locking circuit for itself at armature 38 and at armature s 47 and 38 opens the locking circuit of relay 37 which deenergizes and is unable to reenergize during the connection.

The operation so far described has simply served to indicate the destination exchange at the originating exchange, but no charge has yet been made for a connection, this 01 course not taking place until the wanted subscriber replies. When this happens, as is well known, the back bridge relay 32 operates and reverses the direction of current flowing over the trunlrconductors 23 and 24 as previously described, so that the relay 31 and subsequently relay 3O energize. The energization of relay 31 is identical with that following the energization of relay 30, but the resultant operation is without effect as this repeater is located at an inter mediate exchange. The repeater E however is lo ated at the originating exchange No. '1 where metering has to take place, and consequently, the operation following the energization of relay .30 will be described in full. On the closure of armature '[lof relay Ell, a preliminary energizing circuit is closed for relay 72 as follows: Earth, armature 71 and its wo-rking contact, resistance 73, ind

tery. The resistance v73 is sufficiently great to ensure that the relav TZcannot operate fully but only sufficiently to bring its armature 7.4: into connection with its iront contact.

once per revolution by means of the cam 60. irssumingtherefore, that earth is connected .to lead 75, after armature 74 has been attracted, the relay '72 can fully energize and therebyattract its armatures 7679; at armature 78 relay 72 establishes a locking circuit for itself, while at armature 76 a circuit is prepared for the release magnet 80.

bit ari'nature'77 the release trunk conductor '81 which is normally connected through arn'iature 82 of release relay 26 to earth on spring is connected to wiper 55 and thence via contact 57 to common lead 59 and earth on springsS. Everything is now in order for the sending of the booster impulses.

As will be seen from Figure 1, the meter M is connected to the release trunk conductor 81 through the working contact of armature 86 of the cut off relay '87 of line switch C and thence through wiper 87, bank contact 88, working contact 89 of switching relay 9() to wiper91 and bank contact 92. The meter M is so designed that it will not operate under normal conditions, but will only operate whenbooster battery is connected to the release trunk conductor, so as to increase the current through it. Consequently, the cam 63 will operate the springs 84 to place booster batter on the lead 59 three times during a revolution of the cam shaft, thus operating the meter three times. Just prior to the conclusion of the revolution, the cam 61 operates its .con-

armature 76, the circuit of the release magnet 80. Therelease magnet therefore enci gizes,and remains energized until the wiper 56 reaches its normal position, when battery is disconnected and release magnet deenergizes as also the relay 72. Conditions are therefore restored to normal. As the release trunk conductor at the intermediate exthe call has been set up. For instance, by reference to Figure 5, li/ 'Wlll be noted that exchanges Numbers 1, 3, 7, 8,11, 13 and 15 could all be charged at unit rate for subscribers connected to exchange No. '1. It

will therefore be noted that, the 'lst, 1

The ari'nature 74 is connected to a common lead to which earth is connected 1 tact springs 93 to connect earth to the commonlead94; thereby completing through 7th, 8th, 11th, 13th and 15th contacts are all connected to the lead 95 to which one lead 95 and to which one booster impulse is connected once per revolution of the cam shat; at that e' change. In view oi the recteriu arrangements ha g been ellcctivcly cut (hit, on the release of the switches Q nd to normal, it will be appreciated that the relc oi the connection takes place in the usual way without in any way aiiecting the metering arrangements.

In the special case of calls local to an exchange in which connections there will necessarily be no repeaters, it would be necessary either to provide a special switch. say at the first selectors designed to respond to the booster impulses transmitted on the operation of the wiper relay, or alternatively rrangements would be provided for sending a unit impulse for the release trunk conductor which in the case ot' a local call of course extends throughout the connection. The arrangement for eitecting this is shown in Figure 3. On the energiza ion of the back bridge relay 32, when the wanted subscriber replies, a circuit is closed for relay 100 as follows :-Earth, working contact of armature 101, back contact of armature 102. resistance 103, relay 100 to battery. The resistance 103 is sulliciently great to preventrelay 100 fully energizing, and at this time. it only energizes suii'iciently to attract its armature 104-. Armature 10a is connected to common lead 105 to which earth 1L- \nected once per revolution by means of the can shaft 106, so that not until the cam lllii is in a certain position can the relay U00 lully energize. lVhen it does so, it attracts its armatures 1.0T-100 inclusive. At

.l't. 109, it completes a 1 citing cirall through back contact of armaure E10, armature 100 and its working conact, resistance 103, relay 100 to battery. Resistance 103 per 1 sul'licient current to pass through relay 1.00 to hold it energized, although. not sutficient to permit it to enc The earth on the release trunk con- (i tlLtOl which is received through the springs controlled by armature 10S and armature 1 ll oi release relay 112 is replaced by earth on the common lead 113, to which a booster impulse is connected on the operation of springs 11% b y the cam 113 once per revolution. This booster impulse therefore serves to operate the meter once, and is followed by the closure of the springs 116 by the cam 117, whereby earth is connected to the lead 118 which causes the energization of the left hand *inding of relay 119 through armature 10?. Relay 11S) therefore energizes, and at its armatures 110 and 102 breaks the locking circuit of relay 100, while at arn'iature 102, it completes a locking circuit for its right hand winding and at ar1nature 120, an auxiliary locking circuit is conn -ed to the release trunk conductor for its r ht hand winding. The duplicate locking circuit for relay 100 is provided in order to ensure that the metering is effected it either the called or the calling subscriber should hang up the receiver before the metei' is completed, while the dual locking circuit for relay 119 is provided to ensure that the relay cannot deenergize until both subscribers have hung up their receivers, thereby preventing the metering being repeated during a call.

In lli 'urc it, an alternative arrangement tion to automatic telesystoms in which the first digit ...ed utter access has been gained to a repeater is suiiicient to determine the destination of a call. in order to describe this arrai tent, only that part 01? a repeater sinnl 1 to .ih'WlllQll is n cessary to undere tion o causing the energization of the relay 13-11, are adapted to cause the energization the magnet 130 in the following circuit =rth, armature 135, and its resting contact, iature 136 and its working contact, series relay 13?, oil normal springs 13S and 1539, magnet 130 to bat"ery. The magnet 130 p ads to the first digit to advance the ulse. circuit through the vertical magnet 30 iter the oil norn'ial springs have been opei...ed to their alternate position through the springs 1&3 and 139, so that the i et responds to all the impulses in the first digit trai iitted after the repeaters are seized. lvipers 110 and 142-1 thcretore advance accordingly and the cons are connected in a similar manner to that described with rcii'crence to the switch except that it is the ntuuher of the party called instcaeil. oi a sic-rial number allocated which determines the party required. mentioned before, in certain cases, it is possible that the first digit diallct utter the seizure of the repeater will be su'tiicient to determine the destination e change, and therefore no further provision is necessary. I

it will be noted that the leads from the contacts are sin'iilar to thecoinrnon leads 95. (i6, 59 and 67; while 3 leads on the right hand of the switch are identical with those V other,

leading to armature 76, armature 7'? and the winding of relay 72, so that the subsequent operation of the charging arrangements is identical with that described with relation to Figure 2.

Cliwiously, after the one set of impulses has been transn'iitted by a repeater, the relay 37 'deenergiaes and other impulses will only be effective in operating the relay 15a following standard practice. If it was desired to have a switch designed to respond totwo digits by the repeater, this would obviously be provided but it is doubtful whether it would not prove too expensive. It should be mentioned that the dotted connections to armature 79 and its working contacts are provided in order to prevent the release of the connection in case the calling subscriber should hang up before the metering has been properly effected. The energization of the release relay by armature 79 effectively prevents this as will be understood.

It will be understood that the arrangements shown are only given by way of example, as obviously, several modifications could be made in the manner of carrying the invention into effect without departing from the spirit of'the invention.

Having now particularly described and ascertained the nature of our said invention, and in what manner the same is to be performed,

lVhat we claim as our invention is:

1. In a telephone system embracing a number of exchanges, means for establishing connections from one exchange to antrolled from the called exchange for deter-- mining the charge to be made for the call, and circuit arrangements such that the exercise of the control is delayed until a plurality of series of digit impulses are transmitted to the called exchange.

2. In a telephone system embracing a number of exchanges, means for extending connections from calling lines in any exchange to a called line in any other exchange, a code interrupter in each exchange which sends a code of impulses to the calling exchange whenever a call is extended thereto, means in the calling exchange remeans in the calling exchangecom' c range, and means in each of said other ex-' changes for assessing the required toll responsive to said impulses.

t. In a telephone system having arbitrarily established zones of calling, with established rates for calls extending between zones, means for establishing connections from one zone to another direct or through a number of intervei'iing zones, and selective means in each exchange controlled from the called exchange for charging at the proper rate regardless of the number of intervening exchanges or zones.

A telephone system in which there are a number of exchanges, and means for ex- 0 tending connections between exchanges, means in each exchange when" called for transmitting a special series of impulses characteristic of that exchange, and means in each exchange when calling responsive to the impulses from the called exchange for determining the charge to be assessed for the call.

6. A telephone system in which there are a number of exchanges, and means for extending connections between exchanges, means in each exchange when called for transmitting a special series of impulses characteristic of that exchange, and means in each exchange when calling responsive to the impulses from the called exchange for determining the charge to be assessed for thecall, independent of the route taken by the call.

7. In a telephone system consisting of a plurality of exchanges locatectat varying distances from each other and requiring different rates of toll for calling between the various exchanges, means associated with each exchange for sending a definite number of impulses to any exchange calling that exchange, and additional means in each exchange operating in response to the impulses received from the particular called ex change for determining the proper rate of charge.

8. In a telephone system comprising a number of exchanges, means for setting up connections between lines in said exchanges, a selecting device'loca'ted in the exchange'in which the call originates for determining the charge to be assessed for the call, said device controlled solely from the exchange in which the line called is located.

9. In a telephone system comprising a plurality of exchanges, a code sending device for each exchange operating to transmit a special series of impulses indicative of that particular exchange, over any connection extended to that exchange, and a selecting device in each exchange operated when that exchange is calling, which responds to the series of impulses from the called exchange to assess the charge for the call between the two exchanges.

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10. In a zone metering telephone system, a plurality of exchanges, a selecting device in each exchange having a plurality of contact sets, one set for each of the other exchanges, means in each exhange operable when calls are received for setting the selecting devices in the exchanges where the calls originate, each selecting device being always set on the particular contact set corresponding to the *alled exchange, and circuit arrang ments and apparatus by means of which each selecting device controls the assessing of charges against calling lines which vary in accoi dance with the exchanges to which the calls are extended.

11. l a Zone metering telephone system, a firs exchange, a plurality or other or;- changes, automatic switches -lor connecting calling lines in any of said other exchanges with called lines in said tirst xchange, a device in saie lirst exchange for transmitting a series of impulses to the calling exchange each time a call is received, the number of impulses being fixed and independent of which exchange is calling, a selecting device in each of said other exchanges adapted to respond to such series of impulses to always select a particular contact set, and circuit connections to the contacts sets in said selecting devices which vary in accordance with the exchanges in which the selecting devices are located so that calling parties in different ones of said other exchanges may be charged different amounts for calls to said first exchange.

19,. In a telephone system en'ihracing a number of xchanges, means for establishing connections from one exchange to another, means in the calling exchange determining the charge to be made for the call, and means operative responsive, to the seizure of the line called for rendering the means in the calling exchange etlective.

13. In a telephone system consisting of a plurality of ext-ha ges located at varying distances from each other and requiring ditl'erent rates 01" toll for calling between the various exchanges, a plurality of meter operating devices associated with each ex change, means also associated with each exchange for sending a definite number of impulses to any exchange calling that exchange and additional means operative in response to the impulses received from the particular called exchange for selecting a particular one of said meter o3erating devices to determine the proper rate oi charge.

list. In a telephone system comprising a plurality of exchanges, a plurality of meter operating devices, a selecting device located in the exchange in which the call originates for selecting one of said meter operating devices to determine the charge to be assessed for the call, said selecting device controlled solely from the exchange in which the line called is located.

15. In a telephone system compriing a plurality of exchanges, means for extending connections from tire calling lines in any exchange to a called line in any other exchange, continuously operating impulse transmitters for starting, transmitting and stopping the transmission oi a code of impulses to the calling exchange whenever a call is extended thereto to determine the charge to be made for the call, means operative responsive to the seizure of the line ca led to connect one of said impulse trans initters to cause said means to operate further at the appropriate time to also connect the other of said transmitters, and means responsive to the actuation of one of said transmitters to disconnect all of said transmitters after the charge determining impulse code has been sent.

16. in a telephone system embracing a plurality of exchanges, means for establishing connections from any one exchange to any other, automatic switches and pulsing elements at each exchange, impulse contact operated by said pulsing elements having connections terminating in the banks of the said automatic switches located at their respective exchanges, other pulsing elements at each respective exchange, and means for causing one of said other pulsing elements of any exchange to transmit impulses to any other exchange calling it to operate a said automatic switch of such calling exchange to select one of said first pulsing elements to determine the charge to be made for the call.

17. In a telephone system embracing a number of exchanges, means including a connector switch for establishing connections from lines of one exchange to lines of the same or another exchange, a line switching relay and a bacl; bridge relay in said connector, means in the calling exchange controlled by the switching relay of said connector, when the call originates in another exchange, to determine the charge to be made for the call, and other means controlled by the back bridge relay to actually reg. er the charge when the calling and called exchange is one and the same.

Signed by me at Liverpool, England this 9th day of Sept. 1921.

CHARLES GILLINGS.

Signed by me at Liverpool, England this 9th day of Sep. 1921.

RICHARD MERCER 

